Engine Upgrade

This blog covers status of the work to convert the Rotax 912 into a supercharged engine.

Overview
The factory has undertaken a period of testing that has validated the FlyGas Supercharger upgrade, this modification has proven safe but remains an experimental engine, so for those seeking more power with a proven record the factory is recommending the proven Rotax 914 or maybe a Rotax 915 when available.

The existing 912 mechanical fuel pump does not cope with the extra fuel flow demanded by the supercharger and requires the installation of two [2] electric fuel pumps. The 912 pump will cope once the power is reduced to below 100 hp so this does provide a mechanical backup in the event of a total electrical failure [i.e. regulator] but is messy requiring two pumps and their electrical demand with a limited alternator output.

A product known as a "Billet Pump"  was marketed in the US using a piston pump for engines up to 400 hp using carburettors or low-pressure fuel injection but appears to have been removed from sale by the supplier. Robert Borger's Europa has a conversation and had other pilots interested but the supplier would not respond but is happy with the performance of the pump. A single electric pump will be fitted and operate in a similar manner to any low wing aircraft.

Robert Borgers Billet pump installation

Robert has provided all the information on his pumps 
construction aiding the design of a new installation

After a lot of research starting with the patent number, it was discovered this was a modified automotive product so it was decided to replicate the original design intent and this will be covered in a later blog. This is a proven concept so its anticipated there will be no operational issues and once proven I will make available all the drawings and STP files for the machining as an educational package once I work out how to remove the existing adaptor. When done a 3D model will be developed to mount the pump on the Rotax and sent out for CNC machining. 

Another upgrade is the installation of a Silent Hektik regulator that allows an output of 20 amps from the existing alternator, additionally, a water-cooled oil cooler from the same company is to be incorporated to tidy through the air flow through the cowl.

Reference: DOG Aviations RV12 - interesting reading

Note:  I have found the VANS RV 8 / 12 an excellent source for information and validation.

To assist in creating a more directed air flow a top mounted cooling hood used on the VAN RV12 is to be installed, this was selected over the same item from Rotax, it's a 1/4 of the cost. It will be feed from a 2'' NACA duct located on the lower port side of the cowl.

RV12 Air Hood
It will be fitted to the rear to gain as much
clearance as practical but can be modified

Engine
The installation of the supercharger requires the installation of decompression rings lowering compression to 8: 1 preventing detonation at a boost of 6 psi. All this work is to be undertaken by Joe Newman an RAA L2 as I am time and skilled challenged in this area and Joe has an engine mount at his hangar at Rylstone, it is now hoped the work can begin in July. 

Joe will be keeping a photo log that will be published in this blog with any of his notes on assembly issues. The manual from FlyGas is very comprehensive as is the kit so these notes will fill the gaps.

Comment
Finally redesigned the intercooler and now has all its detail drawings prepared and will be sent out for manufacture locally. Once complete and installed it will be included in an update but it's smaller and a LOT lighter by mounting directly on the engine mount.

Other items - there a lot of jobs at various stages but there is a long wait for parts coming from mainly the USA creating increasing time between the posts, regrettably in Australia it's an industrial wasteland....!